Dresser is more snug around stomach (9)
I believe the answer is:
costumier
'dresser' is the definition.
(I have seen 'theatrical dresser' mean 'costumier' so perhaps 'dresser' could also mean 'costumier')
'more snug around stomach' is the wordplay.
'more snug' becomes 'cosier' ('cosy' can be a synonym of 'snug').
'around' indicates putting letters inside.
'stomach' becomes 'tum' (synonyms).
'cosier' placed around 'tum' is 'COSTUMIER'.
'is' is the link.
(Other definitions for costumier that I've seen before include "Tom Cruise (anag)" , "The person that dressed" , "Supplier of stage clothes for actors" , "fashioned by me" , "One making clothes" .)